Sintering



@et l2, 1937 F. R. McGE'E y S INTERING 7 sheets-sheet `1 Filed Feb. 27, 1936 Oct. 12, 1937. l

F. R. MOGEE SINTERING Fired Feb. 27, 193e '7 Sheets-Sheet 2 [ma/dof. PE4/VK E.. MSGEE,

/Js a/wys. l

0d; 12, my; l FRMCGEE 2,095,567

SINTERING Filed Feb. 27, 195e 7 sheets-*sheetsv ,7 75- 7/) i NIW @s MMM-v F. R MCGEE Oct.. 12, 1937.

SINTERING Filed Feb. 27,` 195.6 '7 Sheets-Sheet 4 @ct M, 1937',

F. R. MCGEE SINTERING '7 Sheets-Sheet 5 Filed Feb. 27, 1936 Patented Oct.

This invention is or blast-roasting o SllNTlERlNG Frank R. McGee, Steubenville, @hic application reti-nary 27, i936, senat-No. 66,115 s claims.' (ci. 26o- 21) concerned with the sintering f oresor metallic compounds in general but particularly of light, dusty compounds.

One of the objects is to make the sintering of light dusty material, of which blast-'furnacel flue-dust is an excellent example, a more healthful and less unpleasant occupation. Another is to increase the efciency with which material of this general character may be sintered. Still another is to sinter in such a manner that it is not necessary to force a draft fan to handle hot air carrying erosive particles. Other objects and advantages may, of course, be inferred from the following disclosure of a specic example of the invention. This example is illustrated by the accompanying drawings, in which:

Figure 1 lis a sectioned elevation. Figure 2 is a sectioned plan from the line II-II in Figure l.

elements of Figure direction.

5 but looking in the opposite sintering is carried out by forcing air at a pres sure greater than atmospheric downwardly through the grate I. This is accomplished by introducing air at a pressure greater than atmospheric to the enclosure t by way of the tangential inlet 5, this air forcing its way downwardly through the grate l to effect the desired sintering, and discharging into the chamber 6 from whence it leaves by the latters outlet 8, the baffle 9 retarding the escape of dust. Dumping of the segments 2 discharges sintered material into ther ner of a dust-catcher its top tapers, and its general proportions ar'e such that this tapered top meets the outer one of the walls 3, these walls being of sufcient depth to not only bound the Figure 'lis a sectional enlargement taken from vthe line VII-, VII in Figure 1.

Figure 8 is a sectional enlargement fromlv the line'VIII-VIII of Figure 1.

It is to be understood that these drawings take certain liberties with the strict rules of mechanical drafting in the interests of clarifying the structural and operating features ofthe invention.

This example of of a complete sinte the invention is in the form ring plant built around a' circular grate I having a series of `dumping segments 2 and bounded by cylindrical walls 3 provided into this chamber.

vblast-furnace dust- This chamber 6 is built like a. catcher in that it is provided with suitable refractory protection, has atapered' material-receiving section provided with a stand ard motor-operated discharging gate I of .the rotating type, anoutlet 8A and a downwardlyflaring baille 9 for retarding the escape of dust by way j of this outlet.

, 'operators without allowing air to escape.

The present invention is characterized -in that grate I but to also provide an annular passageway leading into the top of the chamber 6. The space within the inner one of these walls is closed by a refractory protected partition IIJ.

The -enclosure Il is of sufficient diameter to provide a reasonable working space around the -periphery of the grate l, and'is provided with a working floor II on which operators may stand, the enclosure also being provided with a revolving door l2 for permitting the entrance of these This oor II should also'be provided witha suitable refractory covering for protecting the feet of operators against the heat.

Although automatic machinery will presently be' described, it might be well at this point to note that the operators who must always be on hand in any plant to see that things are going A well are working under reasonably healthful and comfortable conditions. Instead of the usual objectionable conditions prevalent in conventional sintering plants, these operators are working in a relatively clean, cool atmosphere of slightly compressed air which is constantly exiting through the grate I and thus automatically keeping the chamber 4 cleared of dust and, to a considerable extent, heat. The vautomaticv machinery justk mentioned will now be .-desf'.zribed.v 1

A circular track I3 encirclesthe outer one of the walls 3y that bounds the circular grate I, and

a turntable I4 ridesthis track on wheels I5. This turntable mounts a pug mill .I6 powered by a suitable unit I8. 4'I'hispugmill is provided with an inlet I9 that is arranged atthe axis of rotation of the turntable' I4, and with an outlet l2|) arranged over the -circular grate I to feed into the same by way off a` swinging spreader v2l.

When this pug mill is operated and the turntable I4 is rotated, a means traveling over the circular grate I for feeding material to the same is there- 'by provided. Rotation of the turntable I4 may be effected by motors 22 suitably connected to the wheels I5 by Way of gearings 23.

A hopper 24 is built in the conical top of the v enclosure 4 so as to empty into the inlet I9 of the pug mill I6, and this hopper is in turn fed through this conical roof by a suitable conveyer 25 powered by a motor 26 and receiving material from bins 21. This conveyer includes a conduit 28 which passes through the conical roof of the enclosure 24 and which is closed by a gravity operated door 29, this door being forced open by the advancing material during feeding operations. 'I'he escape of air by way of the conduit 26 is prevented by the material in the same and by the action of this gravity operated door.

As a means for bracing the turntable I4 the hopper 24 is made relatively strong and mounts a series of rollers 29 which ride against a ring 39 carried by the inlet I9 of the pug mill I6, the latf)ter also being made relatively strong and being rmly fixed to the turntable I4. This feature also prevents the wheels I5 from jumping the track I 3.

It has been previously Imentioned that the circular grate l has a plurality of dumping segments 2. These are xed to hollow shafts 3l that are journaled in the walls 3 so that turning of the shafts results in dumping of the segments. In each instance the outer ends of these shafts 3l `are provided with operating levers 32 Whose ends are provided with pairs of rollers 33. When the grates I are horizontal the inner ones of these rollers 33 are engaged by latches 34 operated by springs 35, it being possible to force these levers 32 out of their latched positions. To do this the end of the turntable I4 most adjacent the outlet 20 of the pug mill I6 carries a cross-head 36 powered through a connecting rod 31 by a crank 38 operated by an electric motor unit 39. This cross-head 36 is provided with bearing surfaces 40 of suilicient lengths to permit their operating the levers 32 while the turntable continues to travel, the outer ones of the rollers 33 on the ends of these levers 32 rolling on one or the other of the surfaces 40 at such times. i The motor unit 39 is controlled by a push-button 4I through a conventional electric system,

the button 42 of this switch being operated byv one end of a two-armed lever 43 provided with a shifting fulcrum 44 and having a roller 45 on its other end, which is normally engaged by a' cam 46 carried by the crank 38. The buttonoperating end of this lever 43 is pivoted to a depending rod 41 that includes a spring arrange.

ment 48 that continuously urges the lever 43 towards the button 42, movement of this lever being normally prevented by the cam 46 which prevents its other end from moving downwardly. A series of xed pins 49 project horizontally from adjacent the base of the circular rail I3,'and the lower end of the rod 41 is provided with a roller 50 which strikes these pins and rides up over them as they are successively encountered.

The lower end of this rod 41 is mounted by a lever system 5I of such character that when it is swung backwardly by momentary contact with one of the pins 49 it causes the fulcrum 44 to shift sufficiently to permit the roller 45 to'slide/ unit 39. Since the turntable is continuously moving the roller 59 eventually clears whichever one of the pins l49 it may have ridden over, and a spring 52 is xed in 'the lever system 5I to cause the fulcrum 44 to then shift back towards its normal position, whereby movement of the cam 46 during rotation of the crank 38 eventually brings the cam 46 against the roller 45 and lowers the button contacting endof the lever 43, whereupon the motor u nit 39 stops operating. This motor unit 39 ,should include the conventional quick-stopping brake.

In this manner the cross-head 36 is forced through one complete reciprocative cycle every time one of the pins 49 is passed. This dumping action occurs in such a manner that the grate segments 2 are successively dumped slightly in advance of the previously described feeding means, thus leaving empty grate segments to be lled by the latter. that the described elements provide a means operated by the approach of the feeding means for successively dumping the grate segments 2.

Before leaving this phase of the invention a further detail is to be noted, namely, that the turntable I4 also mounts a breaker wheel 53 in front of the material feeding apparatus and a burner 54 behind this apparatus, the breaker functioning to prepare sintered material for the dumping operation and the burner functioning to fire newly fed material. the breaker 53 may consist of a wheel of suitable strength having a toothed periphery,y while the burner or ignition means 54 may be of the conventional type and provided with the required 'i air and gas by way of pipes 55 which extend downwardly through a vertical shaft 56 that passes concentrically down through the hopper 24, and which communicate with the burner in any suitable fashion. 'I'he breaker 53 may be rotated by contact with the material or, and this is illustrated, it may be powered bya motor 51 through a suitable chain drive 58. This breaker is further illustrated as being carried by the turntable I4 on the end of a lever 59 that pivots about the shaft of the motor 51 and which carries an Another Way of saying it is.

More specifically,

adjustable weight 60 whereby the weight applied v to the material by the breaker may be varied.

Returning to the grate I, it is to be noted that the annular space beneath the dumping segments 2 is divided by walls 6I to form separated passageplane of the lower edge of the deector 62, and

the walls 6I which divide the annular space between the walls 3 are provided with extensions 64 which also reach to the plane just mentioned. It is no'w obvious that each of the dumping segments 2 dumps into its own individual passageway and that the various boundaries of this passageway are in the same horizontal plane.

From what has already been said it is apparent that a draft is constantly passing from the enclosure 4 to the chamber 6 by way of the grate I. Now it is apparent that a large amount of material will be blown down through the grate Aneath the dumping grates.

accuser during the time it is being fed by the previously described feeding arrangement and possibly. to some extent, prior to its ignition by the burner 54. A tubular shaft 65 pivotally depends from the center of the turntable I4 through a liquid seal 66 and terminates in a right angularly extending,

arm 61 that carries a door 68 at its end, this door being positioned to slide along the lower edges.

of the various boundaries of the passagewaysvbe- The depending shaft 65 is provided with another but oppositely extending arm 68a which carries a weight 69 that more than counter-balances the Weightl of the arm 61and door 68, whereby this door is constantly fictionally 'pressed into engagement with the lower edges of the previously mentioned boundaries. If the shaft 65 were rtatively fixed respecting the turntable I4 it would result in the door 68 being moved successively past the various 'Y passagewaysso as to thus cut off the draft and although it is turned by the turntable this is done through a lever 1I) having aroller '1I on its end that rides a circular cam 12 fixed adjacent the Vtop of the inner one of the walls 3. This cam 12 has notches 13 between which relatively long declining portions 13a are interposed.

A part of the turntable I4 pushes the lever 1Il around with it through a bell-crank 14 and a con.-

necting rod 15; the end ofthis connecting rodI being provided with a bumper 16 that contacts an abutment 11 formed on this part of the turntable upon slight rising of the lever 18.' This end of the connecting .rod is also provided with an p extension 18 that rides in a' slot formed inthe abutment 11 to maintain` accurate alinement of tl'ieivarious parts. As the drawings showllthis connecting rodI 15 is pivoted to one; end ofthe bell-crank 14, the other end of the latterbeing connected through a suitable slip joint to the piston rod 19 of a iiuid motor. 88 powered by' a sec` ond fluid motor 8l whose piston lrod 82 is constantly/urged downwardly by a weight 83. ,y A

y suitable system of valves 84 is provided for inter-- connecting these two fluid motors, and both motors arecarried by the turntable I4. y

y Nowfwhen the turntable I4 revolves the shaft 10. will "stand still untilsuflicient force is created by displacement of the weight 83 to overcome the "restraining effect exertedby the roller being in one of the notches 13. 'When this occurs the weight 83 will fall and drive the shaft 10 ahead of it, the roller 1I on the end of Vthis shaft quickly riding down one or another of the'declining portions 13a of the circular cam 12 until it catches in the next of the notches 13. rDouble notches are illustrated because of the curity they aord.

The above action results in the advance of the door 68 in a series Iof jerks with pauses between jerks. The contour of the cam surfaces of the added stopping secam 12 and the arrangement 4of the other partsl connecting the pieces of the invention under discussion are such that the Weight 8 3 is`being raised kfunctions-to induce drafts through the same. arrangement is shown particularly well by Fig-v during lthe time the grate segments are being that this door is quickly advanced to close'the passageway beneath a just-dumped segment, whereby the feeding means may deposit material onto this segment while the draft. is shut 0E through the same. It is in thismanner that the draft is stopped during the feeding of the material to the grate segments in the case of the illustrated example, but it should be remembered that other, though possibly less efficient, elements may be substituted. l

An endeavor has been made in this specication to describe the operation ofthe illustrated example during the course of the description of the various details. It is hoped that this has been done so well that a lengthy description of the operation of the plant in toto is unnecessary and such is accordingly not given. 'I'here are.

various subsidiary details that are illustrated and which have not been described. These are heredumped in the already described manner and so inafter mentioned in the interests of disclosing what is obvipusly a completely operative plant in every detail. y I l The hollow shaft 56 that carries the gas and air supply pipes for the burner 54 is also adapted to carry water which may be introduced by way of an inlet 85. This and the inlets 55 all connect with the shaft 56 through suitable connections 1 that permit rotation of this shaft. At least some of the water thus introduced to the plant is passed through the tubular shaft 65 that depends from the turntable I4 and thus to the tubular arm 61 carried by this shaft. y The end of this tubular arm-mounts the door 68 by means of right angularly extending arms 86 and the front one of these arms is provided with an orice 81 through which the water sprays on the material falling` through lthe immediately ypreceding passage from that being closed by the door 68 and through which;v as has been described, thematerial is being dumped. The door cast iron in view yof the heavyservice it performs. It has previously been described that the grate segments 2 are keyed to hollow. shafts 3l, and

it is possible to air-cool these shafts by rotatively connecting them with upturning stacks 88 which The 'ure 3. 'I'his figure also showsl a furtherfeature,

namely, that each of the dumping segments 2 strikes pipes 89. when atthe;extreme of their dumping motions and thusrelieve the cross-head 36. and its associated elements from the task of so doing. Since this pipe will'receive considerable -itself is illustrated as being constructed from heat and since it is convenientlylocated, it is A water-cooled, the waterbeing introduced 4from a 'circular header 90 that encircles the top of the chamber 6 at a point just beneath' the door II- on which the operators stand, by way of valved pipes 9|. The innerends of these pipes are provided with depending outlet pipes 92 that empty into the top of the chamber 6 close to the lower edge of the wall 63, whereby sinteredlmaterial collecting in this chamber is constantly cooled lfrom the moment it begins its entrance to the same. The resulting steam is, of course, blown through the outletl of thischamber by theconstantly exiting air.

It will be appreciated by anyone familiar with sntering that the turntable I4 revolves very slowly, since time must be permitted for complete sintering. In the interests of safety, the endsA of the turntable Mare provided with housings 93- that enclose the various motorized elements mounted there. Still in the interests of safety, there should be clearance between these housings and Athe cylindrical wall of the enclosure 4 so that the operators will not have to keep moving with the turntable. Thus, in the case of the disclosed example, air is forced downwardly through the grate at a pressure greater than atmospheric but many of the advantages of the variousoperating mechanisms are retained if this feature is substituted by a draft induced by evac-` uation. As a matter of fact, it may be desirable to operate the, plant so that thepressure in the chamber beneath the grate is less than atmospheric even when the enclosure above -is supplied- With air under pressure. i

Although the invention has been disclosed inthe form of a specific example of a sintering plant,

it is to be understood that it is not intended to4 stantially air-tight enclosure being arranged over said grate and the rstand second named means to which air maybe introduced at a pressure greater than atmospheric.

3. Sintering apparatus including a circular grate having a series of dumping segments, means traveling over said grate forl feeding material thereto, ignition means traveling over said grate behind the first named means, means for` dumping said segments vin advance of the rst named means, a substantially air-tight enclosure for the top of said grate and the rst and second named means to, which air at a pressure greater than atmospheric may be introduced, a substantially air-tight chamber for the bottom of said grate adapted to receive material dumped from said segments and having an outlet through which air passing downwardly through said grate may exit, and means for stopping the draft from said enclosure to said chamber through said segments while they are being fed material by the first named means.

4. Sintering apparatus including a circular grate having a series of dumping segments, means traveling over said grate for feeding material thereto, ignition means traveling over said grate behind the first named means, means for dumping said segments in advance of the rst named means, a substantially air-tight enclosure for the top of said grate and the first and second named means to which air ata pressure greater than atmospheric may be introduced, a substantially air-tight chamber for the bottom of said grate adapted to receive material dumped from said segments and having an outlet through which air passing downwardly through said grate may exit, andmeans for stopping the draft from said enclosure to said chamber through said segments while they are being fed material by the rst named means, the third and fourth named means being automatically operatively responsive to movement of the first and second named means.

5. Sintering apparatus including a circulary grate having a series of dumping segments, means traveling over said grate for feeding material thereto, ignition means traveling over said grate behind the rst named means, means operated by the approach of the first named means for successively dumping said segments, an air-tight enclosure for the top of saidgrate and the rst and second named means to which air 'at a pressure greater than atmospheric may be introduced, an air-tight chamber for the bottom of said grate adapted to receive material dumped from said segments and having anoutlet through which air passing downwardly through said grate may exit, means operated by the approach of the rst named means for stopping the draft from said enclosure to said chamber through said segments that are being fed material by the first named means, means for feeding material through said enclosure to the first' named means in an airtight manner, means for removing material from said chamber in an air-tight manner and. baiile means for retarding the escape of dust from said chamber by way of said outlet.

6. Sintering apparatus lincluding a circular grate having dumping segments, and a dustcatcher of the blast-furnace type into the top of which the bottom of said grate concentrically opens, said dust-catcher spreading downwardly from said grateto provide a chamber of a diameter substantially greater than said grate, and which is concentric therewith, converging down- Wardly from said chamber to provide a collector for dust and the sintered material and having an outlet for gaseous products from said grate.

FRANK R. MCGEE. 

